1. Field of the Invention
The present invention relates to an image conversion method of smoothing image movement in three dimensional display (abbreviated as “3D solid display” hereinafter) that allows images recorded such as on a film to be viewed three-dimensionally and to an image conversion apparatus using the method.
2. Background Art
Conventionally, there is known a method of presenting different images for the right and left eyes as a method of providing images recorded such as on a film to be viewed three-dimensionally. When a person views an object, a visual difference (abbreviated as parallax hereinafter) occurs between the images seen by the right and left eyes. Owing to the parallax, a person perceives an object as its stereoscopic image and senses depth of the object. Hence, 3D solid display is available by creating and using two pieces of image data (abbreviated as “parallax data” hereinafter) reflecting the parallax between both right and left eyes. Parallax data is created through shooting an object with two cameras of the same type positioned at the right and left for the right and left eyes, respectively.
As a method of 3D solid display using parallax data with a display device, active shutter method is disclosed (refer to Japanese Patent Unexamined Publication No. 2002-262310, for instance). In the method, image signals for the right and left eyes are arranged in time series for display. Then, images for the right and left eyes are viewed by the right and left eyes, respectively, using shutter glasses that open and close the shutters of the lenses for the right and left eyes in accordance with the image for 3D solid display.
Meanwhile, the movies are receiving attention as image sources for 3D solid display and have been achieving widespread use in recent years. In most cases, an image is filmed at 24 Hz (24 frames per second) for recording. Hence, with conventional two-dimensional display, a method is disclosed (refer to Japanese Patent Unexamined Publication No. 2001-333391, for instance) that converts the frame rate of an image from 24 Hz to 60 Hz suitable for image display with the 3-2 pulldown process.
With the above conventional method, each frame of an image recorded on a movie film is displayed alternately between three times and twice, impressing a viewer with the image being timewise discontinuous (judders), which fails to provide a smoothly moving image.